This invention relates to a color display device including a plurality of picture cells each constituted by a plurality of luminous units emitting lights different in luminous color from each other, and more particularly to an improvement in a pattern by which a plurality of picture cells each are divided into luminous units.
Color graphic display devices which have been conventionally known in the art include display devices constructed on the basis of various display or luminous principles such as, for example, a fluorescent display device, a plasma display device, a liquid crystal display device, an EL display device and the like. Such color display devices each are generally constructed in such a manner that a display plane is constituted by a number of picture cells, each of which is then divided into a plurality of luminous cells emitting lights different in luminous color from each other.
Now, a fluorescent display device will be described by way of example. The fluorescent display device includes anodes constituting a display plane. The anodes each are constructed of a number of picture cells, each of which is divided into luminous units of red (R), green (G) and blue (B) luminous colors. Thus, driving of each of the luminous units of the picture cells for luminescence in any desired manner permits a desired color image to be displayed on the display plane by a combination of the colors.
FIG. 7 shows an example of a pattern of dividing of picture cells in a conventional fluorescent display device which is an example of a color display device. A plurality of picture cells constituting a display plane each are constructed of two rectangular luminous units arranged adjacently to each other in a longitudinal direction. More particularly, the picture cells each are separated into two luminous units by a dividing line extending in a lateral direction. Referring now to, for example, two luminous units 1-1A and 1-1B in FIG. 7, the upper luminous unit 1-1A emits light of a green luminous color and the lower luminous unit 1-1B emits orange-colored light. Thus, the luminous cells each constituted by two green and orange-colored luminous units are arranged in a pattern of m rows and 2n columns, resulting in constituting a long-sideways rectangular display plane or a display plane which has a length increased in a lateral direction as compared with a longitudinal direction. In FIG. 7, reference characters 1G to nG designate control electrodes arranged in correspondence to the rows of the picture cells.
In the fluorescent display device thus constructed, for example, subsequent scanning of the control electrodes and feeding of a display signal to the luminous units of each of the picture cells at a suitable timing permit any desired character, image or the like to be not only displayed in three colors on the long-sideways rectangular display plane but scrolled in any desired direction.
Unfortunately, dividing of each of the picture cells into the luminous units in such a pattern as shown in FIG. 7 often causes a failure in display of a line continuous in a particular direction. Now, a situation that two Japanese kanji characters "", which correspond to "Futaba" in Roman characters, are respectively displayed in two single-colors as shown in FIG. 8 in such a pattern of arrangement of the luminous units as shown in FIG. 7 will be considered by way of example. In FIG. 8, the character "" is displayed in a green color by the upper green luminous unit of the two luminous units constituting each picture cell, whereas the character "" is displayed in an orange-color by the lower orange-colored luminous unit. Such display of each character in each single-color by each of the two picture cells vertically or longitudinally divided from each other fails to permit each of lines in any direction other than a lateral direction to be continuous. Thus, lines extending in a longitudinal or oblique direction each are rendered discontinuous due to formation of a gap between the luminous units. This causes visual observation of the character displayed in the single color to be hard, leading to a deterioration in visibility of the display.